TRANSCRIPT

NARRATIONEastern Antarctica, near Casey Station. This is no carefree summer on the coast. Scientists are braving a hidden world entombed in thick ice to investigate a looming catastrophe. They want to discover if Antarctic marine life can survive ocean acidification.

Dr Jonny StarkWe increase the acidity for a period of 10 to 12 weeks and see who are the winners and who are the losers in potentially our future oceans.

NARRATIONSeemingly small changes have massive consequences.

Rob KingThe changes that are happening to our planet now are just so much faster than what we've seen in the geological record.

NARRATIONOcean acidification has been called the 'other CO2 problem' or more sensationally 'global warming's evil twin'. It's directly linked with what's happening in the atmosphere. The last 50 years have seen an accelerating rise in concentration of atmospheric carbon dioxide. More CO2 in the atmosphere inevitably means that more dissolves in sea water, increasing the acidity. Oceans are acidifying more rapidly than at any time in the last 300 million years. When CO2 dissolves, it reacts with water to form carbonic acid, carbonate and hydrogen ions, which decreases the pH. On average, surface pH has already dropped by 0.1 since 1750.

Dr Jonny StarkWe're expecting to see by the end of this century a change of 0.4pH. That doesn't sound like much, but it's actually roughly 2.5 times more acidic than the ocean currently is.

Mark HorstmanOf all the carbon dioxide soaked up by the oceans, most has been by the Southern Ocean. It's deep, windy and rough, so compared to other oceans, more water is stirred up and exposed to the atmosphere. The water is cold, and the colder the water, the more CO2 it can dissolve.

NARRATIONSo polar waters acidify the fastest. Which brings Jonny Stark and his team to Antarctica for the Free Ocean Carbon Enrichment, or FOCE, experiment.

Dr Jonny StarkWhat we're doing is we've got these specially designed seabed chambers, four of them, which we're deploying onto the seabed over existing communities of animals and plants. Two of those chambers will be acidified and two of them will be controlled at ambient conditions.

NARRATIONThis site had been selected because the thriving seabed is less than 20m under the ice.

Dr Jonny StarkThings like sponges and starfish and sea urchins and sea cucumbers, all the sorts of things you'd find in other parts of the world, but these are unique species to Antarctica.

NARRATIONThe success of the experiment depends on the sea ice staying stable and not breaking out. And it's a challenge to install. Equipment on the surface has to be connected to the chambers on the seabed through a small window in the ice.

Team memberAlright, it's going down with a lift bag on it.

Dr Jonny StarkSo the sea ice that we're standing on is a fantastic platform. We've got about 2.5m of sea ice here so it's very thick, very strong.

NARRATION69 large cylinders of CO2 will add to the carbon dioxide already in the sea water to simulate the concentrations in a future ocean.

Dr Jonny StarkEach of these chambers is connected to a 40m long duct. The acidified water is introduced at one end and it mixes with the local water that's flowing through that duct.

NARRATIONIt's tough, painstaking work for the team of ten divers in freezing temperatures for an hour at a time. But there's nothing quite like diving under ice.

Dr Jonny StarkWhen you first get into the water early in the season, underneath the ice, the visibility is just incredible. We're talking hundreds of metres of visibility. It's kind of hard to estimate how far you can see. Water is very still and everything settles out, which means, by the end of winter, it's very, very clear.

NARRATIONAnd the aim is to keep it that way. Each long yellow duct is fed into the water to the divers, who suspend it from the ice ceiling. It's a feat of coordination above and below to stretch them out to their full length before lowering the ducts slowly to the sea bed. The trick is not to drop them.

Dr Jonny StarkThere's a really fine layer of silt on the bottom over the top of everything. We're trying not to disturb that 'cause that could influence the experiment.

NARRATIONThe four perspex chambers are eased through the hole and carefully taken to the seabed to be hooked up to the pumps. The target pH in two of the chambers is about 7.7, 0.4 units less than the current pH, making it more acidic. That's the level at the end of this century if our emission rates don't change. Testing its effect on a patch of Antarctic sea floor is the first experiment of its kind in the world. But what of the ocean depths where small crustaceans swarm in vast numbers?

Mark HorstmanWith a population size of about 800 trillion, the Antarctic krill is one of the most abundant animals on the planet. They may not be huge, but their combined weight is greater than all the humans on earth. And while they're food for everything that's bigger than them, the krill are the powerhouse of the entire Antarctic ecosystem.

NARRATIONIn their lab near Hobart, Rob King and So Kawaguchi put krill eggs to the acid test.

Rob KingWe found that if you expose krill eggs to high concentrations of carbon dioxide, they simply don't hatch. The question then was exactly at what point does that occur? Where is the tipping point for Antarctic krill embryos?

NARRATIONThe answers they found are alarming.

Rob KingIf we continue to emit carbon dioxide in a business-as-usual case, then by the end of this century in some of the major spawning areas for Antarctic krill we'll see hatch rates drop to 50% of their current level. And then, by the year 2300, we'd expect to see less than 2% of the current hatch rate, which is really a collapse of the ecosystem because krill are just so key.

NARRATIONThe knock-on effects of krill collapse are dire.

Rob KingIf we really decimate the krill population, then the animals that are perfectly designed for eating krill, such as the great baleen whales - the blue whales, the fin whales, the minke whales - they surely are going to reduce in numbers.

NARRATIONKrill are particularly vulnerable because their complex life cycle exposes them to naturally high CO2 concentrations in deeper water. Eggs laid at the surface have to sink to a depth of at least 1km before they hatch. Krill then go through 11 larval stages as they ascend to the surface to feed under sea ice. New tests will see how CO2 affects their swimming behaviour.

Rob KingThey can't start feeding when they hatch. They've got to get all the way from 1,000m deep to the surface with the reserves given to them by the female krill that had laid them. So if they're having to put out huge amount of energy into controlling pH balance inside them, they might not have the reserves to make it all the way.

NARRATIONBut one thing is already clear and it offers some hope.

Rob KingIf we go for a low emission scenario, that's where we're very confident that we'll be able to limit the hatch rate reduction to only about 10%.

NARRATIONBack in Antarctica, the FOCE experiment is in its final stages.

Dr Jonny StarkIt's running right now. It's acidifying as we speak. Be really interesting to see what the results are. That's why we're doing this experiment, to get some kind of idea what our future ocean might look like and what we might have to start doing now to help protect it.

NARRATIONCheck our website for updates on the Antarctic experiment as the results come in, and find out more about the secret lives of krill.

EDITOR'S NOTE: In response to a viewer's question about the evidence for the statement that "oceans are acidifying more rapidly than at any time in the last 300 million years", Catalyst provides the following clarification.

In "The Geological Record of Ocean Acidification" (link below), the authors state: "... the current rate of (mainly fossil fuel) CO2 release stands out as capable of driving a combination and magnitude of ocean geochemical changes potentially unparalleled in at least the last 300 My of Earth history, raising the possibility that we are entering an unknown territory of marine ecosystem change."

In 'Ocean Acidification Summary for Policymakers – Third Symposium on the Ocean in a High-CO2 World", 540 experts from 37 countries said: "Todays human-induced acidification is a unique event in the geological history of our planet due to its rapid rate of change. An analysis of ocean acidification over the last 300 million years highlights the unprecedented rate of change of the current acidification. The most comparable event 55 million years ago was linked to mass extinctions of calcareous deep-sea organisms and significant changes to the surface ocean ecosystem. At that time, though the rate of change of ocean pH was rapid, it may have been 10 times slower than current change."

We also noted that the Intergovernmental Panel on Climate Change (IPCC) said in its Fifth Assessment Report (2014): "The key environmental issue of the 21st century is one of an unprecedented rate of change, not simply magnitude, of CO2 levels. The current rate and magnitude of ocean acidification are at least 10 times faster than any event within the last 65 Ma (high confidence) or even 300 Ma of Earth history (medium confidence)."

So to better reflect the qualifications in the research papers, it would be more accurate to say "oceans may be acidifying more rapidly than at any time in the last 300 million years."

YOUR COMMENTS

Let's assume for this exercise that Dr Jonny Stark has a sleep disorder and cannot sleep without the help of a sleeping pill... For years Dr Stark has taken his one pill regularly before bedtime. Now, setting aside the accoutumance effect, at, say 5 mg a pill a day of 'active ingredient',over a year, Dr Stark would have ingested 1,800 mg of that drug; over a period of 10 weeks, Dr Stark would have ingested 350 mg. Now, Let's just give Dr Stark such a dose - 350 mg in a single take and let's study the effect... shall we?

Somehow, I am confident that different studies have been made regarding the effect of the increase of C02 in the atmosphere on the acidity in sea water as well as impact on animals/plants in a greenhouse and their results would not have been made public.

Incidentally, who is financing Dr Stark's project please ?

Mark Horstman - 24 Apr 2015 9:58:11am

Public funding - a Linkage Infrastructure, Equipment and Facilities grant from the Australian Research Council; an Antarctic Gateway Partnership grant from the ARC; and funding from the Federal Government's Australian Antarctic Science program through the Australian Antarctic Division

ghl - 26 Mar 2015 10:43:43am

You tell us of an experiment to determine a "tipping point ", the Ph that effects krill. The experiment has produced some dire predictions for the year 2300, so it has produced some figures. Why didn't you give us the figures? What are you, PR flacks?

Mark Horstman - 26 Mar 2015 11:52:00am

PR flack? Why no ghl, just a good science journo. Perhaps you missed the answers to your question in the story, from one of the scientists (Rob King) who conducted the experiment and produced the data. In summary: under business-as-usual (BAU) emissions scenario, krill hatch rates drop 50% by 2100. BAU by 2300, drop to less than 2% of current hatch rate. Low emissions scenario, hatch rate reduction limited by about 10%. These emissions scenarios are the Representative Concentration Pathways for CO2 used by the IPCC in their projections. The full results are in the journal article at http://rsbl.royalsocietypublishing.org/content/early/2010/10/07/rsbl.2010.0777 (link also provided on this story page at the end of the transcript).

Mark Horstman - 26 Mar 2015 12:16:27pm

In addition, the krill research measured the pH in terms of CO2 concentrations in seawater. Seawater CO2 concentration is directly linked to pH. As you can see in their paper, seawater CO2 is measured in micro-atmospheres (µatm). This is directly related to atmospheric CO2 concentrations, measured in parts per million (ppm). When atmospheric CO2 concentration is 400ppm (for example, which is very close to the global average now), the seawater concentration is 400 µatm.

The research showed that high carbon dioxide concentrations are lethal for krill eggs. The tipping point begins at around 1250 ppm, to a lethal concentration around 1750ppm. The years these concentrations will occur are based on the various emissions scenarios.

Thanks for your question. More information is in the extended interview with Rob King at the top of this page.

Emile Morel - 28 Mar 2015 4:50:57pm

A question for your experiment as it progresses

Since approximately 50% (depending on who you read) of atmospheric oxygen comes from plant life (from phytoplankton to larger plants) in the ocean, at what ph level in the acidification process will it affect the ability of this plant life to survive and produce oxygen?